Anders Hoveland
Enlightened
- Joined
- Sep 1, 2012
- Messages
- 858
https://www.youtube.com/watch?v=lHD657EGoCY
The insides of a Viribright 8W LED bulb, note the heat sink. It is not a piece of thin aluminum, it is solid/heavy like the heat sinks used in car electronic fan speed controllers. Between the upper heat sink and the lower heat sink there are solid metal nipples like features acting as heat pipes.
Pealing away one of the phosphor rubber caps you can see the LEDs which are clearly not warm white. Philips developed a remote phosphor sheet that converts the blue light into white. This is normally done right on the surface of the LED, but putting distance between the phosphor covering and the LED offers several advantages, such as better color consistency, avoiding color shift caused by the phosphor layer heating up, and slightly higher efficiency as well.
The plastic cover is solvent welded (glued) on all along the rim. It takes time squeezing the cap to break most of the weld, and a few small flat screwdrivers to wedge the clips open. Once inside, there is a screw in the middle holding the 2 heavy heat sinks together. Each LED board has a single screw holding it to the top heat sink. Screws are well tightened and sufficient heat sink compound used. If you take the top heat sink off you can get to 3 more screws to remove the lower heat sink, but I did not go that far. It would require desoldering the 2 wires that go down to the power supply.
(note: these pictures were not taken by me)
What is so interesting about this LED bulb is it does not just use blue LEDs. The interior of the bulb contains 6 sections, and within each of these sections there is a U-shaped row of 12 emitters- 9 of them blue and 3 of them red LEDs. Apparently the red emitters are to help give the light better color rendering and provide higher efficiency, so it is similar to the Philips L-prize bulb in this respect.